Regulation of Recombinant PKCα Activity by Protein Phosphatase 1 and Protein Phosphatase 2A

The sensitivity of PKCα to two protein phosphatases (PP1and PP2A) has been studied. The results show that both phosphatases reversibly inhibit PKCα activity suggesting an effect at PKC autophosphorylation sites and not at transphosphorylation sites. Moreover, PP1has been found at low concentration to activate PKCα implying the existence of an inhibitory phosphorylation site. Further, PKCα has been shown to phosphorylate PP2A at its regulatory subunit B.